Iran could become involved in a regional strategy to the conflict in Afghanistan, as Tehran shares common interests with the United States there, suggested General David Petraeus, head of US Central Command.

A resolution to the ongoing conflict in Afghanistan requires "a regional approach ... that includes Pakistan, India the Central Asian states and even China and Russia, along with perhaps, at some point Iran," Petraeus said at a conference organized by the Institute of Peace think tank.

"There is a common interest between Afghanistan, the coalition (of foreign forces in Afghanistan) and Iran, but there are also major conflicting interests, needless to say," said Petraeus, who is in charge of US operations in Afghanistan and Iraq.

"I am happy to leave that element of the regional approach to the diplomats and policymakers," he added.

Remnants of the hardline Taliban regime, which was ousted from power in the US-led invasion in late 2001, are now waging an insurgency against the US-backed government of President Hamid Karzai.

There are about 70,000 international troops in the country fighting alongside Afghan security forces to quell the Taliban.

Petraeus emphasized that Iran is "conflicted" over the situation in Afghanistan.

"Clearly they don''t want to see Afghanistan in the grip of ultra-fundamentalist extremist Sunni forces, as is the case with the Taliban, but nor do they want to see the narcotics problem get worse," he said.